Cobbe v Yeoman's Row Management Ltd [2008] UKHL 55

Mr Cobbe, an experienced property developer, reached an oral arrangement with Mrs Lisle-Mainwaring, who controlled Yeoman's Row Management Ltd. He would seek planning permission to redevelop a block of flats, after which the property would be sold to him under financial terms discussed in principle. Both understood that the arrangement was not a binding contract and that further essential terms remained to be negotiated. Cobbe spent substantial time and money obtaining valuable planning permission. Once permission was granted, Mrs Lisle-Mainwaring withdrew from the arrangement and demanded a significantly higher price. Cobbe claimed a proprietary estoppel, a constructive trust or restitution for the benefit conferred. The lower courts granted proprietary relief, and the company appealed.

Could proprietary estoppel enforce expectations created during commercial negotiations where both parties knew that no binding land contract existed and material terms remained unsettled?

The House of Lords rejected proprietary estoppel and a constructive trust. Cobbe knew that the arrangement was legally incomplete, subject to further negotiation and unenforceable without the required formal contract. There was no sufficiently certain assurance of a defined proprietary right on which he could reasonably rely as already secured. Equity could not use estoppel to remove consciously accepted contractual uncertainty between experienced commercial parties. However, the company had accepted the valuable planning services in circumstances making it unjust to retain them without payment. Cobbe was therefore entitled to restitution on a quantum meruit basis reflecting the value of his services, rather than the expected development profit or an interest in the land.

Proprietary estoppel requires a sufficiently clear assurance of rights in property and reasonable detrimental reliance. In commercial negotiations, a party who knows that the arrangement is non-binding and materially incomplete cannot ordinarily use estoppel to obtain the bargain, though restitution may compensate an accepted benefit.

Cobbe emphasises certainty and statutory formality in commercial land transactions. It does not confine proprietary estoppel to domestic promises, but context affects whether an assurance is clear and reliance reasonable. The case contrasts with Thorner v Major, where indirect assurances in a family setting were sufficiently clear because the property and expected inheritance were understood. It also distinguishes expectation relief from restitution: Cobbe could recover the value of services that produced planning permission, but not the speculative profit of the unenforceable development arrangement. Later cases caution against treating Cobbe as a universal 'commercial context' bar.